The atmosphere surrounding the surface of the earth has a great influence on human life. Among the observation systems used for recognizing the structure and change of the atmosphere, a radiosonde has temperature, humidity and GPS sensors mounted thereon in such a manner as to be carried into the atmosphere by a balloon, thus allowing the upper air state of the atmosphere to be recognized through observation materials transmitted therefrom at given time intervals,
Temperature, air pressure and humidity are measured directly by the radiosonde elevated into the air, and wind is measured by calculating the flying distance of the balloon during a given period of time. Generally, there are a LORAN (Long Range Navigation) method and a GPS (Global Positioning System) method for recognizing the position of the radiosonde.
For example, Korean Patent Registration No. 10-1045827 discloses a rising-and-falling type of lower atmosphere observation and testing device, wherein temperature and humidity are observed through various sensors and if the corresponding observation signal and position signal are transmitted to ground, precise observation result values are recognized.
The radiosonde is elevated into the upper air, and as it goes high, it is exposed to rain or passed through cloud, so that the humidity sensor may be wet, thus causing errors in the measurement of humidity.
So as to prevent the humidity sensor from being brought into direct contact with water, the humidity sensor of the conventional radiosonde is covered with a cap.
However, the conventional cap has a structure of surrounding the humidity sensor, so that external air is not rapidly circulated to the humidity sensor located inside the cap, thus making the response speed of the measurement of humidity undesirably decreased.
Accordingly, there is a definite need for the development of a new dual cap capable of preventing the humidity sensor from being brought into direct contact with water and improving the response speed of the measurement of humidity.